(Reuters) – Blackstone Group LP is close to a deal to buy a 50 percent stake worth $1.2 billion in a gas field in Louisiana currently owned by Royal Dutch Shell, according to a person familiar with the matter.

The shale assets lie in the Haynesville Shale in Louisiana and Texas. Shale gas, or natural gas trapped in layered rock, has revitalized the U.S. gas market by providing an abundant new supply source.

The source asked not to be identified because the discussions are private.

The Wall Street Journal was first to report the news on Sunday. A representative for Blackstone declined to comment. A representative for Shell said it does not comment on speculation or rumor.

Shell entered the region in 2007 through a joint venture with Canadian energy company Encana, the newspaper reported.

A deal would add to Blackstone’s energy holdings in Louisiana. In February 2012, Blackstone agreed to invest $2 billion in Cheniere Energy Partners LP, a deal that helped Cheniere finance construction of a gas-liquefaction plant in Louisiana for export markets.